Steam-generator.



No. 784,432. PATENTED MAR. 7, 1905. O. RENARD.

STEAM GENERATOR.

APPLICATION FILED JUNE 27,1904.

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C. RENARD.

STEAM GENERATOR.

APPLICATION 21mm JUNE 27,1904.

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PATENT OFFICE.

STEAM-GEN ERATOR.

SPECIFICATION forming p r of Letters Patent No. 784,432, dated March 7, 1905.

Application filed June 2'7, 1904. Serial No. 214,385.

To (all whom it may concern.-

Be it known that I, CHARLES RENARD, colonel ofengineers, a citizen of the French Republic, residing at Meudon, Seine-et-Oise, France, have invented certain new and useful improvements in Steam-Generators, of which the following is a specification.

My invention has for its object to provide an improved steam-generator wherein water is evaporated with great rapidity, the evaporation taking place in a coil into one end of which the water is injected under pressure by a feed-pump, while the steam issues from the other end of the coil.

in the accompanying drawings, Figure l is a diagrammatic section of a steam-boiler,showing the feeding arrangements of feed-water. Fig. 2 is a diagrammatic section of the same steam-boiler, showing the feeding arrangements of gaseous fuel and the furnace. Fig. 3 is a plane section through the furnace. Figs. 4 and 5 show diagrammatically the circulation of water, and Figs. 6 and 7 the circulation of water and fuel, in the generator. Fig. 8 is a detail view of the coils for water, steam, and fuel. Fig. 9 is a section through line a a, Fig. 8. Fig. 10 is a section through line I) b of Fig. 8. Fig. 11 is a section through line 0 c of Fig. 8. Fig. 12 is a section through line (Z (Z of Fig. 8. Fig. 13 is a section through line e e of Fig. 8.

The furnace of the steam-generator is situated beneath the evaporating coil and is adapted, preferably, to burn liquid or gaseous fuel; but it may be adapted to burn solid fuel, if desired. 1 will presume that liquid fuel is used. It is first completely vaporized, for which purpose a pump 1, Fig. 2, forces the liquid fuel into a coiled tube 2, preferably arranged about midway of the water-evaporating coil 3. \V here the liquid fuel is not light like alcohol and petrol, for examplebut is a heavy hydrocarbon oil, the temperature of the region of the boiler in which the oil-evaporating tube is situated should be just sufiicient to volatilize the liquid fuel without decomposing it and producing coke. The construction of the water-evaporating coil 3, which is closely packed, is such that the temperature of the gases from the furnace varies along the said coil according to a regular law, the said temperature being at a maximum at the bottom of the coil and at a minimum at the top thereof. It is therefore easy to find by trials the part of the boiler which is suitable for the oil-vaporizing tube 2, so that the oil is vaporized without being decomposed and provides a combustible vapor for burning in the furnace.

The furnace consists at least of three concentric casings 4: 5 6. The inner casing a is of refractory and inoxidable metal (nickel or nickel-steel, for example) and is the furnace proper. Air forced into the furnace by a fan 7 first enters the outer. casing 6 and then passes into the intermediate casing 5 by ascending the annular space between the outer casing and the intermediate casing, and then it descends between the intermediate casing 5 and the inner casing L, so that the said air becomes heated in the circuitous path which it has to take before reaching the lower opening of the inner casing or furnace proper. By this arrangement the outer casing 6, which is in contact with cold air only, does not radiate heat to the surroundings, whileair reaches the furnace proper at such a high temperature that the heat of the flame is at its maximum intensity. At the base of the furnace proper, t, is arranged a burner 8, Fig. 3, which consists of arose or the like distributing in a regular manner the liquid fuel through numerous small apertures arranged within the air-inlet opening to the furnace proper. A perfect mixture of air and combustible vapor is thus insured, together with the production of a short and smokeless blue flame. The escape of the burned gases takes place through a chimney 9, which is formed so as to prevent the roaring noise which would otherwise be caused by the intense draft. The said chimney is made of two conic frusta 9 and 10, connected together at their smaller ends 11, the small sectional area of the chimney at this part preventing the aforesaid noise. The upper conic frustum 10 is long enough to act as a reducer of pressure or a diffuser,counteracting the injurious effects of the narrow section, which would otherwise oppose a great resistance to the flow of the gases. If the furnace be fed with gaseous fuel, the gas is forced directly into the burner 8 by a fan, the delivery of which relatively to the air is so calculated as to effect perfect combustion.

The steam-generator proper, situated above the furnace, consists of a coil 3, inclosed in a light double casing forming a water-jacket 12, preferably square in cross-section. The feedwater from a feed-watertank 13 circulates at a pressure little more than that of the atmosphere through the jacket 12, wherein it is constantly renewed either by a pump 14 or by gravity, and in the latter case a float-valve will maintain a constant level in the jacket. The water thus preheated in the jacket 12 is drawn therefrom by a feed pump 15 and forced into the water-evaporating coil 3 by a suitable pipe 16. This arrangement has the advantage of protecting the jacket against the destructive effects of the temperature of the gases and reduces the external radiation to a minimum without it being necessary to use a protective lining ofrefractory materials. The complete steam-generatingcoil comprises two zones namely, an upper zone A, in which the water flows downward through the convolutions of the coil, and a lower zone B, in which the steam generated ascends through the convolutions of the coil, Figs. 4:, 5.

The coil of the upper zone A contains only water or very wet steam, and the passage of the gases and the passage of the water take place in opposite directions, whereby the maximum of thermal efliciency is thus secured.

In the lower zone B, which acts as steamdrier, the passage of the steam and the passage of the gases are in the same direction; but the arrangement avoids the burning of the lower convolutions of the coil, which would occur if these convolutions contained only dry steam. The arrows on Fig. 5 show the circulation of the water and of the steam in the coil 3. When liquid fuel is employed, the coiled tube 2 for the vaporization of the liquid fuel may be situated in the region of the 7 upper zone A; but it may be arranged in a -zone C, comprised between the upper and lower zones A and B, Figs. 6 and 7. The circulation through the oil-vaporizing tube 2 preferably takes place in an upward direction; but it may take place in a downward direction, if desired, as shown in Fig. 7.

The heating-surface of my improved steamgenerator consists in practice of a large number of horizontal tubular grids formed of S- shaped coils with closely-arranged parallel straight portions, the said grids being superposed in such a manner that the straight portions of any one coil are at right angles to the straight portions of the coil or coils next it. The said tubular grids may be connected together by brazing or by autogeneous soldering, and they should be in contact or without spaces between them in a vertical direction. The tube constituting the steam-generating coil may have a constant diameter throughout; but generally for large powers the diameter may be increased gradually toward the bottom that is, toward the region where steam is formed, Fig. 8.

The water is delivered at the top of the up per steam-generating zone through the inlet 17, while the outlet 18 for the steam from the lower zone is also on the top of the generatorcoil.

19 is the inlet of the liquid fuel in the coil, and 20 the outlet of the combustible vapor to the furnace.

The thermal efficiency of the steam-generating coil is nearly ninety per cent. even when the draft is very powerful, and this efiiciency is almost independent of the conditions of working.

I have described only the general arrangement of a steam-generator having a single steam-generating coil; but several coils-say four or nine, for examplemay be arranged within the same casing, each generating-coil 3 being fed by a special pump, and the same applies to the oil-vaporizing coil 2, so that the distribution of theliquids within the coils will always be equal and prevent the rapid destruction of any of them. If solid fuel be used, the oil-vaporizing coil 2 and its accessories are of course dispensed with.

An additional application embodying the improvements in furnace and chimney with respect to the particular construction of the latter was filed by me November 26, 1904, Serial No. 234,393.

Having thus described and ascertained the nature of my invention and in what manner the same may be performed, I declare that what I claim is 1. A steam-generator having a tube in one piece forming a large number of horizontal grids with closely-arranged parallel straight portion-s of alternate coils at right angles to straight portions of the coils between and adjacent to the said alternate coils, a liquid-fuelevaporating coil arranged midway and between the steam-generating coils, a waterjacket surrounding the steam-generator and having means for feeding water thereto, a furnace beneath the generator, and a chimney communicating with the furnace.

2. A steam-generator having a tube in one piece forming a large number of horizontal grids with closely-arranged parallel straight portions, the said grids being superposed in such manner that the straight portions of alternate coils are at right angles to the straight portions of the coils interposed betweenthe alternate coils, a liquid-fuel-evaporating coil arranged midway and between the steam-generating coils, and a casing surrounding the tube and forming a water-jacket with respect thereto.

3. A steam-generator having a tube in one piece forming a large number of horizontal fuel coil being inserted between the members of the tubular coil, both coils being horizontally disposed and having the parts thereof alternately arranged at angles to each other.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

CHARLES RENARD.

Witnesses:

HANSON (J. Coxn, PAUL BLUM. 

